Drip irrigation systems need some pre-winter attention

As I write this, we are looking forward to a weekend of lovely fall weather in the 70s, followed by rain on the valley floor and snow in the mountains. Last week I said it wasn't time to stop watering plants, but it is close.

A colleague asked me today how to winterize the drip system at a school garden she has been working on, a timely fall topic.

Drip systems usually lie above ground and freeze more readily than in-ground systems. Although drip systems are more forgiving than in-ground systems when it comes to freezing, it is important to protect a system's timers, filters, fittings, backflow device and electric valves.

To winterize a drip system, start by turning off the water supply to the system. Uncrimp the end caps of the polytubing and completely drain all parts of water. This will prevent lines from splitting or being damaged. A good way to drain lines is to blow the water out with compressed air at no more than 30 PSI. If you don't have an air compressor, raise one end of the polytube above the other and let gravity do the work for you. After draining is complete, cap the ends of the tubes off to prevent critters, debris and dirt from getting into them.

Bring the timers, backflow devices, filter regulator assemblies and so on into the house or garage and store them in a place they can't freeze. Remove any batteries from the timers to prevent corrosion.

To help in the draining process throughout the year, there are flush valves that can be installed at the end of a polytube line or at a low point in the middle. These valves automatically open up when the water pressure inside the tube drops below a certain pressure. A self-draining line reduces potential freeze damage, especially in those early and late freezes.

After everything has been drained, it is OK to leave the tubing and the emitters outside during the winter. With our winter sun, it doesn't hurt to cover the lines up with mulch, but it is not necessary. If you cover the lines, mark their location, so that when you start digging in the spring you don't damage them with a shovel.

Check out all the hook-up parts, timers, filters and valves and replace any O-rings or washers in preparation for next spring. With a little maintenance, a drip system can last for years.

• JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension and may be reached at skellyj@unce.unr .edu or 887-2252.